Re: WIP: a way forward on bootstrap data

On 4/6/18, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I experimented with converting all frontend code to include just the
> catalog/pg_foo_d.h files instead of catalog/pg_foo.h, as per the
> proposed new policy. I soon found that we'd overlooked one thing:
> some clients expect to see the relation OID macros, eg
> LargeObjectRelationId. Attached is a patch that changes things around
> so that those appear in the _d files instead of the master files.
> This is cleaner anyway because it removes duplication of the OIDs in
> the master files, with attendant risk of error. For example we
> have this change in pg_aggregate.h:
>
> -#define AggregateRelationId 2600
> -
> -CATALOG(pg_aggregate,2600) BKI_WITHOUT_OIDS
> +CATALOG(pg_aggregate,2600,AggregateRelationId) BKI_WITHOUT_OIDS
>
> Some of the CATALOG lines spill well past 80 characters with this,
> although many of the affected ones already were overlength, eg
>
> -#define DatabaseRelationId 1262
> -#define DatabaseRelation_Rowtype_Id 1248
> -
> -CATALOG(pg_database,1262) BKI_SHARED_RELATION BKI_ROWTYPE_OID(1248)
> BKI_SCHEMA_MACRO
> +CATALOG(pg_database,1262,DatabaseRelationId) BKI_SHARED_RELATION
> BKI_ROWTYPE_OID(1248,DatabaseRelation_Rowtype_Id) BKI_SCHEMA_MACRO

It seems most of the time the FooRelationId labels are predictable,
although not as pristine as the Anum_* constants. One possibility that
came to mind is to treat these like pg_type OID #defines -- have a
simple rule that can be overridden for historical reasons. In this
case the pg_database change would simply be:

-#define DatabaseRelationId 1262
-#define DatabaseRelation_Rowtype_Id 1248
-

and genbki.pl would know what to do. But for pg_am:

-#define AccessMethodRelationId 2601
-
-CATALOG(pg_am,2601)
+CATALOG(pg_am,2601) BKI_REL_LABEL(AccessMethod)

I haven't thought this through yet. I imagine it will add as well as
remove a bit of complexity, code-wise. The upside is most CATALOG
lines will remain unchanged, and those that do won't end up quite as
long. I can try a draft tomorrow to see how it looks, unless you see
an obvious downside.

-John Naylor